Improvement in countersinks



No. 108,837. I PATENTED NOV. 1, 1870,

' W. B. SHEDD.

GOUNTERSINK.

tiniest Siam new cum.

WILLIAM B. SHEDD. OF EAST BOSTON, MASSACHUSETTS.

Letters Patent No. 108,837, dated November 1, 1870.

IMPROVEMENT lN COUNTERSINKS.

. ne'scneauie referred to In mm mm. resent and m of the am To all whom it may concern:

Be it known that I, WILLIAM .B. Sunni), of East Boston, in the county of Suffolk and State of Massachusetts, have made an invention of an Adjustable (lountersinking Device for Boring-Tools; and do hereby declare the nature of such invention, and the mode of carrying the same into efleet, to be herein fullywith a bit gimlet, or other boring-tool, of an adjustable counteisinking device, or cutter, by whose agency the hole bored by such tool is at the same time countersunk to any desired or given depth; and

The invention consists in the combination and arrangement of the several parts, as hereinafter described.

In the drawing- A represents a thin flat plate of metal, fashioned into a right-angular yoke or clasp, with its two sides, a b, of equal length or thercabout, a hole, 0, being formed through each side 'in coincidence, these holes being of like size, and equal in diameter to the largest boring-tool which the device will he applied to.

The outer end of each 'side a or b isv formed with an elongated orifice or slot, (1 or e, to receive the shank f of the cutter g, which I have adapted to perform the functions of a countersink. rectangular bar, and its upper end is prolonged into a sloping pyramidal-shaped or pointed steel plate, the edges of which are sufliciently sharp to cut wood or other material, the shank of such cutter being confined in place within the slots 1! e by a thumb or set-screw, h, which screws through it and into a rectangular oblong block of metal which the clasp A receives.

This block of metal is represented at i-in the-accom panying drawing as a rectangular oblong bar, provided with a series of vertical holes, 7.: k, bored through it throughout its length, these holes being of varying I diameters and adapted to receive a series of boringtools of corresponding diameters, while the female screw which receives the set-screw h should be situated in alignment with the ccnterof each hole 1:, in order that the countersink or cutter g shall maintain the same relative 'position with each and every hole when used in connection therewith, or the boringvtool inserted in such hole.

This position of the cutter g is i such that its apex; or point I shall extend into the channel and closely against the least diameter of the cutting portionof the boring-tool, which, as is well known, is, in all boring-tools or nearly all,"quite small, and nearly of uniform extent.

This entrance of the point anda portion of the effective cntting-suriace of the cutter g within the circumference of the cutting portion of the boring-tool,

fonns'a distinguishing feature in my invention, and

'has the eflect of insuring an easy and smooth countersinking of the hole bored by such tool, which would not be the case did the said point recede, in the least dcgrce, from such circumference, as in such an event it would take into the material and describe a circle or score outside of such hole, and estop all further advance.

A bit, of the ordinary gouge pattern, is represented at m, in the accompanying drawing, as inserted within the holes 0 e of the clasp A, and one of the holes k of the block 5 with which it assimilates in diameter, the screw h being advanced against the said tool at with sufficient power to retain the clasp, block, cutter, and toolsecurely in their proper positions, the said cutter, as a conseq'nence, traveling with the said tool when the latter is in revolution.

Olaim.

The herein-described combination of the clasp A, the cutter 9, block 1;, and screw 71, the whole constituting an adjustable countersink for boring-tools, and operating as set forth. WM. B. SHEDD. Witnesses:

FRED. Ounrrs, En. Gnmrrra. 

